A clinically relevant method of analyzing continuous change in robotic upper extremity chronic stroke rehabilitation

BACKGROUND: Robots designed for rehabilitation of the upper extremity after stroke facilitate high rates of repetition during practice of movements and record precise kinematic data, providing a method to investigate motor recovery profiles over time.OBJECTIVE: To determine how motor recovery profiles during robotic interventions provide insight into improving clinical gains.METHODS: A convenience sample (n = 22), from a larger randomized control trial, was taken of chronic stroke participants completing 12 sessions of arm therapy. One group received 60 minutes of robotic therapy (Robot only) and the other group received 45 minutes on the robot plus 15 minutes of translation-to-task practice (Robot + TTT). Movement time was assessed using the robot without powered assistance. Analyses (ANOVA, random coefficient modeling [RCM] with 2-term exponential function) were completed to investigate changes across the intervention, between sessions, and within a session.RESULTS: Significant improvement (P < .05) in movement time across the intervention (pre vs post) was similar between the groups but there were group differences for changes between and within sessions (P < .05). The 2-term exponential function revealed a fast and slow component of learning that described performance across consecutive blocks. The RCM identified individuals who were above or below the marginal model.CONCLUSIONS: The expanded analyses indicated that changes across time can occur in different ways but achieve similar goals and may be influenced by individual factors such as initial movement time. These findings will guide decisions regarding treatment planning based on rates of motor relearning during upper extremity stroke robotic interventions

Meiosis Drives Extraordinary Genome Plasticity in the Haploid Fungal Plant Pathogen Mycosphaerella graminicola

Meiosis in the haploid plant-pathogenic fungus Mycosphaerella graminicola results in eight ascospores due to a mitotic division following the two meiotic divisions. The transient diploid phase allows for recombination among homologous chromosomes. However, some chromosomes of M. graminicola lack homologs and do not pair during meiosis. Because these chromosomes are not present universally in the genome of the organism they can be considered to be dispensable. To analyze the meiotic transmission of unequal chromosome numbers, two segregating populations were generated by crossing genetically unrelated parent isolates originating from Algeria and The Netherlands that had pathogenicity towards durum or bread wheat, respectively. Detailed genetic analyses of these progenies using high-density mapping (1793 DArT, 258 AFLP and 25 SSR markers) and graphical genotyping revealed that M. graminicola has up to eight dispensable chromosomes, the highest number reported in filamentous fungi. These chromosomes vary from 0.39 to 0.77 Mb in size, and represent up to 38% of the chromosomal complement. Chromosome numbers among progeny isolates varied widely, with some progeny missing up to three chromosomes, while other strains were disomic for one or more chromosomes. Between 15–20% of the progeny isolates lacked one or more chromosomes that were present in both parents. The two high-density maps showed no recombination of dispensable chromosomes and hence, their meiotic processing may require distributive disjunction, a phenomenon that is rarely observed in fungi. The maps also enabled the identification of individual twin isolates from a single ascus that shared the same missing or doubled chromosomes indicating that the chromosomal polymorphisms were mitotically stable and originated from nondisjunction during the second division and, less frequently, during the first division of fungal meiosis. High genome plasticity could be among the strategies enabling this versatile pathogen to quickly overcome adverse biotic and abiotic conditions in wheat field

Carbon monoxide inhalation reduces skeletal muscle fatigue resistance.

AIM: To determine whether inhalation of carbon monoxide (CO), resulting in carboxyhaemoglobin (COHb) levels observed in smokers, had an effect on muscle fatigue during electrically evoked and voluntary muscle contractions. METHODS: Young non-smoking males inspired CO from a Douglas bag until their COHb level reached 6%. During the control condition the same participants inspired ambient air from a Douglas bag for 6 min. Fatigue was assessed as the decline in torque in isometric knee extensions, during 2 min of electrically evoked contractions (30 Hz, 1 s on, 1 s off) and during 2 min of maximal isometric voluntary contractions (1 s on, 1 s off). A fatigue index (FI) was calculated as the ratio of final torque : initial torque. Time to peak torque (TPT) and half relaxation time ((1/2)RT) were also determined for the electrically evoked contractions. RESULTS: The FI during both the voluntary fatigue test (control: 0.80 +/- 0.09 vs. CO: 0.70 +/- 0.08; mean +/- SD) and that of the fatigue test with electrically evoked contractions (control: 0.61 +/- 0.09 vs. CO: 0.53 +/- 0.12) was significantly lower after CO inhalation than after inhalation of ambient air (P < 0.05). There was, however, no effect of CO on the changes in TPT or (1/2)RT during the fatigue test. CONCLUSION: Carbon monoxide inhalation resulting in COHb levels found in smokers has an acute impact on the ability of the muscle to resist fatigue